Hydraulic computer for pump by-pass control



April 1965 R. c. SMITH 3,180,266

HYDRAULIC COMPUTER FOR PUMP BY-PASS CONTROL Filed June 27, 1963 iii FIG; 2 7/11! III] 711/ 1 4/ 4 a4 32 T. 42

Ill-III 38 38 V 26 k 52 F 22 I Q i as 4 2a 44 r 1 6 zs FIG. 3 48 3 50 e4 36 so. I

56 INVENTOR. 7 RALPH C. SM/TH a4 54 AGENT United States Patent 3,180,266 HYDRAULIC C(BMPUTER FUR PUMP 'hY-PAEiS CGN'HRGL Ralph C. Smith, Brooklyn, N.Y., assignor to Ingersoil- Rand Company, New Yorh, N.Y., a corporation of New Jersey Filed June 27, 1963, er. No. 290,983 3 Claims. (Cl. itl3-42) This invention relates to pumps, compressors and the like and more particularly to means to control the output thereof.

The present invention is particularly adapted, but is not limited, to boiler feed pumps or similar pumps which normally operate at elevated temperatures and/or pressures. When such a pump operates at reduced flow conditions, there is a danger of pump binding and seizure because of overheating. To deter or prevent overheating present pump systems of the aforementioned type include means for maintaining a minimal feedback or by-pass flow. It is readily understood that maintaining a feed-back or bypass flow during normal pump operation is a power waste.

Accordingly, an object of this invention is to provide a pump that operates at high temperature and/ or pressure levels with normally closed deed-back or by-pass flow means which opens when above normal operating temperatures and/or pressures are encountered.

Another object of the present invention is to provide the foregoing pump feedb ack or by-pass me ans that varies the rate of feed-back orlby-pass flow in response to change of temperature and/ or pressure above normal operating conditions.

Still another object of the present invention is to provide the foregoing pump feed-back or by-pass means in which the value of excessive heat and excessive pressure signals may be varied relative to one another.

This invention contemplates a pump with an inlet line, an outlet line, and a by-pass line connecting the inlet and outlet lines across the pump, a valve disposed in the bypass line and has a spring for biasing the valve closed during normal operation of the pump means in the outlet line for sensing temperature and pressure of pumped fluid and for providing signals representing the sensed temperature :and pressure, and motor means connected to the valve and sensing means for opening the valve in response to signals representing temperature and pressure in excess of normal pump operating ranges.

The ttoregoingand other objects and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with the accompanying drawings wherein several embodiments of the invention are illustrated by way of example. It is to be expressly understood, however, that the drawings are for illustration purposes only and are not to be construed as defining the limits of the invention.

FIGURE 1 is a schematic view of a pump and bypass system made in accordance with the present invention,

FIGURE 2 is an enlarged schematic View of the bypass valve control and operating means of the system of FIGURE 1, and

FIGURE 3 is a schematic view of a modified by-pass valve control and operating means.

Referring now to the drawings, and particularly to FIGURES 1 and 2, a pump id, such as a boiler feed pump has an inlet line @112 to receive fluid to be pumped an an outlet line 14 for the pumped fluid. A line in is in communication with inlet line 12 and outlet line- 14 to provide a pump feed-back or a by-pass from the normal destination of the pumped fluid.

A (normally closed) valve Ed is disposed in line 16 to control the flow of fluid therethrough, and may be of the type shown, described and claimed in US. application '32 and a pressure pickotf 34 to provide pilot pressure signals in accordance with or representative of the tem perature and pressure, respectively, of the pump discharge in line d d. A pair of motors or actuators 4t) and 42 are connected to bulb $2 and pick-ctr 34, respectively, by respective lines 36 and 38, and are responsive to the pilot signals. Motors 40 and 42 are operatively connected to or associated with opposite ends of a ratio bar 26 connected, by a pivot pin r28 or the like, at its midpoint to the valve plunger 22. The connections of motors 4d and 42 to bar as each form the pivot point for the bar 26 when the motor at the opposite end of the bar responds to a change of its pilot signal. Inasmuch as motors 4t) and 42 operate in opposition to the force or bias of spring 24-, they do not require positive attachment and may merely bear on bar 26 as shown in the drawings.

One form of motor construction is shown in FIGURE 2 :wherein motor 4% is comprised of a cylinder 44 and a piston as slidable in the cylinder. Piston 46 has a rod member 43 that extends forwardly through cylinder 44 and abuts the end of bar :26. An anti-friction ball may be disposed in the front end of rod 48. Although not shown, a light rate return spring may be disposed in the cylinder 44' forward of piston 46. Valve Q0 and motors id and 42 are mounted on a platform 50. To vary the value or effect of the pilot signals relative to one another, motors 4t and 42 are movably mounted in a slot or track 52 in platform 59 by worm or lead screws 5% that rotate by a hand wheel 56 for adjusting the distance of the motors from the pivot connection of bar .26 to plunger 22. Inasmuch as the construction mounting, and adjustment means of both motors 4b and 42 are the same as one another, such details are shown only for motor 40.

A modified valve operating system is shown in FIGURE 3 wherein Bourdon tubes 6t: and 62, correspond to motors 4i) and 4.2, have fixed ends 64 and 66, respectively, connected to the respective signal lines as and 38. A pair of variable resistors 72 and 74, such as industrial precision rheo-sats, are connected in series and have respective wiper arms 76 and 73 that pivot on trunnions iitl and 32, respectively. Wiper arms '76 and '78 are pivotally connected to free ends 68 and 7t, respectively, of the respective Bourdon tubes 6t? and 62-. To vary the value of the pilot signals relative to one another, trunnions 8i? and 82 are movably mounted relative to the respective free Bourdon-tube ends as and 7th in a manner correspond ing to the aforementioned adjustable mounting of motors 4-5} and 42. An electrically responsive actuator is connected to plunger 22 to control valve 2i in response to DC. signals from a source 84 as modified by the variable resistors 72 and '74- in accordance with or representative of the temperature and pressure of the pump discharge in outlet line lid. 7

Should either or both of the lines 36 and 33 fail, the resulting actuating force on plunger 22 will become nil, and spring 24 will bias plunger 22 to a full open by-pass position.

Although several embodiments of the invention have been illustrated and described in detail, it is to be expressly understood that the invention is not limited thereto. Various changes may also be made in the design and arrangement of the parts Without departing from the 3 spirit and scope of the invention as the same will now be understood by those skilled in the art.

I claim:

1. In combination with a pump having an inlet line to receive fluid and an outlet line for pumped fluid:

(a) a bypass line connecting the inlet and outlet lines;

(D) a valve connected in the by-pass line having a member movable therein to control the flow therethrough and through the by-pass line, and a spring for biasing the member to a closed position for blocking such flow when the temperature and pressure of pumped fluid are within normal operating ranges;

(c) means connected in the outlet line to sense temperature and pressure of pumped fluid and to provide pilot signals representing such sensed temperature and pressure; and

(d) motor means connected to the sensing means being operatively associated with the valve to move the valve member against the bias of the spring for opening the valve to pass flow therethrough in response to pilot signals representing combined temperature and pressure each in excess of normal operating ranges.

2. In combination with a pump having an inlet line to receive fluid and an outlet line for pumped fluid:

(a) a by-pass line connecting the inlet and outlet lines;

(1)) a valve connected in the by-pass line having a member movable therein to control the flow therethrough and through the by-pass line, and a spring for biasing the member to a closed position for blocking such flow when the temperature and pressure of pumped fluid are within normal operating ranges;

(c) means connected in the outlet line to sense temperature and pressure of pumped fluid and to provide pilot signals representing such sensed temperature and pressure;

(a) a pair of motors operatively associated with the valve each to move the valve member in addition to such movement by the other of the motors against the bias of the spring for opening the valve to pass flow therethrough in response to pilot signals it eceives;

(e) one of the motors being connected to the sensing means to receive pilot signals representing pressure of the pumped fluid in excess of its normal operating range; and

(f) the other of the motors being connected to the sensing means to receive signals representing temperature of the pumped fluid in excess of its normal operating range.

3. In combination with a pump having an inlet line to receive fluid and an outlet line for pumped fluid:

(a) a by-pass line connecting the inlet and outlet lines;

(b) a valve connected in the bypass line having a member movable therein to control the flow therethrough and through the by-pass line, and a spring for biasing the member to a closed position for blocking such flow when the temperature and pressure of pumped fluid are within normal operating ranges;

(c) a bar member pivotally connected at its midpoint to the valve member;

(d) means connected in the outlet line to sense temperature and pressure of pumped fluid and to provide pilot signals representing such sensed temperature and pressure;

(e) a pair of motors connected to the sensing means being operatively associated each with one of the ends of the bar member;

(f) one of the pair of motors being responsive to pilot signals representing temperature to move the valve member by the bar member and against the bias of the spring for opening the valve to pass flow there- 4 through when the temperature of pumped fluid exceeds its normal operating range; and

(g) the other of the pair of motors being responsive to pilot signals representing pressure to move the valve member by the bar member and against the bias of the spring for opening the valve to pass flow therethrough when the temperature of pumped fluid exceeds its normal operating range.

4. In combination with a'purnp having an inlet line to receive fluid and an outlet line for pumped fluid:

(a) a by-pass line connecting the inlet and outlet lines;

(b) a valve connected in the by-pass line having a member movable therein to control the flow therethrough and through the by-pass line, and a spring for biasing the member to a closed position for blocking such flow when the temperature and pressure of pumped fluid are within normal operating ranges, the spring urging the valve member past its closed position to a full open position in the absence of a pilot signal;

(0) a bar member pivotally connected at its midpoint to the valve member;

(d) means connected in the outlet line to sense temperature and pressure of pumped fluid and to provide pilot signals representing such sensed temperature and pressure;

(0) a pair of motors connected to the sensing means being operatively associated each with one of the ends of the bar member;

(f) one of the pair of motors being responsive to pilot signals representing temperature to move the valve member by the bar member and against the bias of the spring for opening the valve to pass flow therethrough when the temperature of pumped fluid exceeds its normal operating range;

g) the other of the pair of motors being responsive to pilot signals representing pressure to move the valve member by the bar member and against the bias of the spring for opening the valve to pass flow therethrough when the temperature of pumped fluid exceeds its normal operating range; and

(11) means for changing the distance of each of the pair of motors from the connection of the bar and valve members.

5. In combination with a pump having an inlet line to receive fluid and an outlet line for pumped fluid:

(a) a bypass line connecting the inlet and outlet lines;

(b) a valve connected in the bypass line having a member movable therein to control the flow therethrough and through the by-pass line, and a spring for biasing the member to a closed position for blocking such flow when the temperature and pressure of pumped fluid are within normal operating ranges;

(0) means connected in the outlet line to sense temperature and pressure of pumped fluid and to provide pilot signals representing such sensed temperature and pressure;

(d) motor means connected to the sensing means being operatively associated with the valve to move the valve member against the bias of the spring for opening the valve to pass flow therethrough in response to pilot signals representing combined temperature and pressure each in excess of normal operating ranges; and

(c) said motor means including an actuator connected to the valve member responsive to DC. signals for opening and closing the valve, and means connecting the actuator to a DC. signal source and varying the DC. signal in response to the pressure signals.

,- 6. In combination with a pump having an inlet line to receive fluid and an outlet line for pumped fluid:

(a) a by-pass line connecting the inlet and outlet lines;

(12) a valve connected in the by-pass line having a member movable therein to control the flow therethrough 7 and through the by-pass line, and a spring for biasing the member to a closed position for blocking such flow when the temperature and pressure of pumped fluid are within normal operating ranges;

(c) means connected in the outlet line to sense temperature and pressure of pumped fluid and to provide pilot signals representing such sensed temperature and pressure;

(d) a pair of motors connected to the sensing means, one being responsive to pilot signals representing temperature and the other being responsive to pilot signals representing pressure;

(e) an actuator connected to the valve member being responsive to D.C. signal for opening the valve to pass flow therethrough when the D.C. signal represents temperature and pressure in excess of normal operating ranges; and

(1) means connecting the actuator to a D.C. signal source being connected to the motors and actuated thereby to vary the D.C. signal in response to changes of the pilot signals.

7. In combination with a pump having an inlet line to receive fluid and an outlet line for pumped fluid:

(a) a by-pass line connecting the inlet and outlet lines;

(b) a valve connected in the bypass line having a member movable therein to control the flow therethrough and through the by-pass line, and a spring for biasing the member to a closed position for blocking such flow when the temperature and pressure of pumped fluid are within normal operating ranges, the spring urging the valve member past its closed position to a full open position in the absence of a pilot signal;

(0) means connected in the outlet line to sense temperature and pressure of pumped fluid and to pro vide pilot signals representing such sensed temperature and pressure;

(a') a pair of motors connected to the sensing means,

one being responsive to pilot signals representing temerature and the other being responsive to pilot signals representing presure;

(e) an actuator connected to the valve member being responsive to D.C. signal for opening the valve to pass flow therethrough when the D.C. signal represents temperature and pressure in excess of normal operating ranges; and

(f) a pair of series connected variable resistors connecting the actuator to a D.C. signal source each being connected to one of the motors and actuated thereby, one varying the D.C. signal in response to change of the pilot signal representing temperature and the other varying the DE. signal in response to change of the pilot signal representing pressure.

8. The combination in accordance with claim 7, and

means for varying the rate of response of each of the variable resistors.

References (fitted by the Examiner UNITED STATES PATENTS 459,384 9/91 Heerrnans 103-42 2,305,933 12/42 Soderberg 236--92 X 3,013,233 12/61 Bourns 73-398 X LAURENCE V. EFNER, Pfiimary Examiner. 

1. IN COMBINATION WITH A PUMP HAVING AN INLET LINE TO RECEIVE FLUID AND AN OUTLET LINE FOR PUMPED FLUID: (A) A BY-PASS LINE CONNECTING THE INLET AND OUTLET LINES; (B) A VALVE CONNECTED IN THE BY-PASS LINE HAVING A MEMBER MOVABLE THEREIN TO CONTROL THE FLOW THERETHROUGH AND THROUGH THE BY-PASS LINE, AND A SPRING FOR BIASING THE MEMBER TO A CLOSED POSITION FOR BLOCKING SUCH FLOW WHEN THE TEMPERATURE AND PRESSURE OF PUMPED FLUID ARE WITHIN NORMAL OPERATING RANGES; (C) MEANS CONNECTED IN THE OUTLET LINE TO SENSE TEMPERATURE AND PRESSURE OF PUMPED FLUID AND TO PROVIDE PILOT SIGNALS REPRESENTING SUCH SENSED TEMPERATURE AND PRESSURE; AND (D) MOTOR MEANS CONNECTED TO THE SENSING MEANS BEING OPERATIVELY ASSOCIATED WITH THE VALVE TO MOVE THE VALVE MEMBER AGAINST THE BIAS OF THE SPRING FOR OPENING THE VALVE TO PASS FLOW THERETHROUGH IN RESPONSE TO PILOT SIGNALS REPRESENTING COMBINED TEMPERATURE AND PRESSURE EACH IN EXCESS OF NORMAL OPERATING RANGES. 